Bag sealing machine

ABSTRACT

A MACHINE FOR FORMING BAGS FROM THERMOPLASTIC LONGITUDINALLY FOLDED FOIL IN WHICH THE FOIL IS INTERMITTENTLY FED TO A SEALING DEVICE IN PREDETERMINED LENGTHS CORRESPONDING TO THE DESIRED WIDITH OF THE BAGS, WITH THE SEALING DEVICE SEVERING THE FOIL AND SIMULTANEOUSLY SEALING THE SEVERED EDGES THEREOF.

I. D. BELLA BAG SEALING MACHINE June 22, 1971 9 Sheets-Sheet 1 FiledNov. v6, 1968 Inventor ITALO DELLA BELLA aygbmwu )MWMQE June 22, 1971BELLA 3,586,577

v BAG SEALING MACHINE Filed Nov. 6, 1968 9 Sheets-Sheet 2 Inventor ITALODELLA BELLA Y g kmlukFEM nNMmLJun a June 22, 1971 I. D. BELLA 3,586,577

BAG SEALING MACHINE Filed Nov. 6 1968 9 Sheets-Sheet 5 Fig. A

Inventor ITALO DELLA BELLA June 22, 1971 D. BELLA BAG SEALING MACHINE 9Sheets-Sheet 4 Filed Nov. 6, 1968 Inventor ITALO DELLA BELLA June 22,1971 L DBELLA 3,586,577

BAG SEALING MACHINE Filed Nov. 6, 1968 9 Sheets-Sheet 5 Fig. 7

Inventor ITALO DELLA BELLA June 22, 1971 l. D. BELLA BAG SEALING MACHINE9 Sheets-Sheet 6 Filed Nov. 6, 1968 Inventor ITALo DELLA BELLA By SQ'fiOu L ki n (MK uh" MAW b June 22, 1971 BELLA 3,586,577

BAG SEALING MACHINE Filed Nov. 6, 1968 9 Sheets-Sheet 7 LA 69 1 L 68 b5A6 32 2Q 110 L? .2 1?: wgk

b3 4'? m Mn 70 Fig.1!

Inventor ITALO DELLA BELLA June 22, 1971 l. D. BELLA 3,585,577

BAG SEALING MACHINE Filed Nov. 6, 1968 9 Sheets-Sheet 8 Inventor ITALODELLA BELLA By \bdCl/n M sh" (U m; y Lu/J June 22, 1971 DQQELLA3,586,577

BAG SEALING MACHINE Filed Nov. 6, 1968 9 Sheets-Sheet 9 1 5 Fig. 7h

3O nu Inventor ITALO DELLA BELLA United States Patent @ffiC6 PatentedJune 22., 1971 US. Cl. 156-351 33 Claims ABSTRACT OF THE DISCLOSURE Amachine for forming bags from thermoplastic longitudinally folded foilin which the foil is intermittently fed to a sealing device inpredetermined lengths corresponding to the desired width of the bags,with the sealing device severing the foil and simultaneously sealing thesevered edges thereof.

BACKGROUND OF THE INVENTION The invention relates to a machine forforming bags from a thermoplastic semi-tubular foil or a foil previouslyfolded in a longitudinal direction, where the foil is fed to a sealingdevice intermittently in proper lengths corresponding to the desiredwidth of the bag, with the sealing device operating to simultaneouslyseparate and seal the foil at the resulting separated edges.

Known bag sealing machines of this type have the disadvantage that inthe feeding device for the foil and in the ejection device for thesealed bags, there must be considerable play or free motion provided toguarantee an easy running, smooth operating process. However, thisclearance or free motion produces considerable differences in the widthof the bags prepared, which in practice may amount to as much as two tothree centimeters.

SUMMARY OF THE INVENTION Accordingly, the primary object of theinvention is to provide a bag sealing machine capable of producing bagsin which the differences in width of the bags produced is unnoticeablysmall. In any event, any differences in width of the plastic bagsproduced will be so small that such bags can be used without anydifficulty in automatic vending machines or other machine installations.

The primary object as set forth is accomplished by the invention inwhich the feeding arrangement for the foil located immediately beforethe sealing device comprises a pair of rollers with a reverse stopmechanism, while the device for taking-up and ejecting the formed bags,located immediately after the sealing device, is provided with a drivingarrangement of its own, controlled, however, by the drive mechanism forfeeding the device. As a result, one predetermined length of foil oncedelivered to the sealing device cannot be pulled back in the reversedirection by the tension device for the foil or other machine parts aswas the case in known bag sealing machines. The predetermined length offoil assigned at one time to the sealing device will thus actuallydetermine and correspond to the final width of the bag.

Another object of the invention is to provide a bag sealing machine inwhich the feeding arrangement for the foil, locked against returnmovement, will hold the foil in constant tension between the tensioningdevice and the feeding device when the feed rollers are stationary, sothat the feeding device operates even at the beginning of the feedingprocess against the tension of the foil and tensioning device, and thuswill become effective only after any play in its drive mechanism hasbeen taken up or neutralized.

Still another object of the invention is to provide a bag sealingmachine in which any kind of jerk at the beginning of the foil feedingstep will be avoided through the maintenance of the constant foiltension between successive feeding steps so that no momentary sliding ofthe feed elements across the foil and no stretching of the foil by sucha jerk can occur.

A related object of the invention is to provide a bag sealing machine inwhich the clearance or play motion in the drive for the feeding devicewill be avoided without any excessively large expenditure of moneyrequired for this purpose.

A further object of the invention is to provide a bag sealing machine ofthe above described type where the driving arrangement for the feedingdevice for the foil contains a crank assembly including a free-wheelingrocking lever drive, which is adjustable to permit adjustment of thedesired width of the bag to be formed.

Still a further object of the invention is to provide a bag sealingmachine of the above described type where the driving arrangement forthe feed device contains an electrically controlled coupling element forthe timely interruption of the driving connection and where electricprobing devices are arranged in the path of movement of the foil or ofthe bags, the probing devices controlling the coupling element tointerrupt the drive connection, with the probing devices beingadjustable along the path of movement of the foil or of the finishedbags to set the desired width of the bags.

Another object of the invention is to provide a machine for forming bagsfrom thermoplastic synthetic semitubular foil or foil previously foldedin a longitudinal direction, the machine comprising a device whichsimultaneously separates and seals the foil at the proper separatededges with a heated separating-welding element guided essentiallyperpendicularly from top to bottom through the foil and subsequentlyreturned between the welded edges to its raised rest position. Anarrangement is provided to lift at least the welded edge of the finishedbag from the area of movement of the separating-welding element as it isreturned to its raised position. Finally, a related object of theinvention is to provide a bag sealing machine of this type in which bothwelded edges are lifted from the area of movement of theseparating-welding element as it returns to its rest position.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevation viewillustrating a first embodiment of the bag sealing machine of theinvention;

FIG. 2 is an enlarged fragmentary view of the section IIII of FIG. 1;

FIG. 3 is an enlarged fragmentary view of the section III-III of FIG. 1;

FIG. 4 illustrates an electric control circuit for the bag sealingmachine embodiment of FIGS. 1 to 3;

FIG. 5 is a view similar to FIG. 1 but illustrating a second embodimentof the bag sealing machine;

FIG. 6 is an enlarged fragmentary view of the section VIVI of FIG. 5;

FIG. 7 illustrates an electric control circuit for the bag sealingmachine of FIGS. 5 and 6;

FIG. 8 is a schematic fragmentary illustration of the foil feedingdevice, of the separating-welding device and of the take-up and ejectiondevice for the bags of a bag sealing machine, with structuralarrangements at the feed side of the foil and at the departure side ofthe finished bags for lifting the welded edges from the path of movementof the separating-welding element;

FIG. 9 is a fragmentary illustration of the cam control mechanism forthe device of FIG. 8;

FIG. is a fragmentary illustration similar to FIG. 8 with the partspositioned at the beginning of the separating-welding processs;

FIG. 11 is a fragmentary illustration similar to FIG. 8 with the partspositioned after completion of the separating-welding process;

FIG. 12 is a view similar to that of FIG. 8 illustrating however onlyone structural arrangement at the departure side of the bags to lift thewelded edge from the path of movement of the separating-welding element;

FIG. 13 is a view similar to FIG. 12, with the parts positioned aftercompletion of the separating-welding process;

FIG. 14 illustrates a third embodiment of the lifting arrangements atthe foil intake side and the departure side of the bags, in which thewelded edges may be lifted from the path of movement of theseparating-welding element in the shape of flaps which can be swungupwardly, with the parts positioned shortly before commencement of theseparating-welding process, and

FIG. illustrates the device according to FIG. 14 with the parts ofpositioned during the return of the separating-welding elements to itsrest position.

PREFERRED EMBODIMENTS OF INVENTION Referring to FIGS. 1-3, a machineframe 1 has two upper lateral carrier and mounting plates 2 facing eachother and carrying a roll of foil 3, a foil feeding device 4, a weldingdevice 5 and a take-up and ejection device 6 for the bags. Between theroll of foil 3 and feeding device 4, and a foil tension and guide devicehas been arranged which is formed by a foil tensioning device 7pivotally mounted on the machine frame 1 and guide rollers 8a, 8b and 8cmounted on plates 2.

The foil feeding device 4 comprises two counter rotating rubber feedrollers (see FIG. 2) contacting opposite sides of the foil web 10. Theserubber rollers 11 and 12 are formed with peripheral grooves 13 withwhich stripper elements 14 engage, in order to guide the foil safelyinto the operational area of the welding device 5.

An electric motor 15 with a built-in automatic locking gear system isprovided for the drive of the foil feeding device 4. Motor 15 throughchain drive 16 drives a control shaft 17, from which, as will beexplained later, the cam mechanism for reciprocating the welding device5 is driven, with shaft 17 also being provided with electric controlelements for the machine.

In FIGS. 1 to 4, crank 18 is fixed on one end of control shaft 17. Thecrank pin 19 is adjustable radially of shaft 17 as shown in FIG. 3. Aconnecting rod 20 is attached to crank 18, 19 and drives a freelyrunning pivoted lever drive 21 on shaft 22 so that every revolution ofthe crank 18, 19 causes a partial revolution of shaft 22 as determinedby the adjustment of the crank element 19. Lever 21 only drives shaft 22when it is pivoting in the direction of the arrow, and when it pivots inthe opposite direction, it is free running on shaft 22. This partialrevolution of shaft 22 is transferred to the axis 24 of lower rubberroller 12 by a chain drive 23. Intermeshing spur gears 26a and 26b areattached on driving shaft 24 of the lower rubber roller 12 and drivingshaft of the upper rubber roller 11. On shaft 25 a one-way freelyrunning drive 27 locks against return revolution of shaft 25, so that aunidirectional drive is provided between shafts 24 and 25. Thus upperrubber roller 11 is driven in a counter direction to but at equal speedrelative to roller 12.

The Welding arrangement 5, as shown in FIG. 2 contains two relativelystationary lower clamping girders 28 which can be provided with acoating on their top side, on which coating the foil 10 that is to befinished will not slip. Opposite to and above the fixed clamping girders28, perpendicularly movable clamping strips 29 are arranged. Theseclamping strips 29 are each perpendicularly movably mounted on and withrespect to guide arms 30 which in turn are perpendicularly movablymounted at each side of the machine. Strips 29 are biased downwardly bysprings 31. Between the guide arms 30 extends the transverse severingseparating and welding wire 32. The two guide arms 30 are secured attheir upper ends to a guide girder 33 extending transversely across themachine, and guide rods 34 at each side of the machine are secured attheir upper ends to girder 33. The guide rods 34 each slideperpendicularly in a guide pedestal 35 attached at the outside of themachine frame 1, and the holding and mounting plates 2 and operatingsprings 36 bias the rods 34 downwardly. Each guide rod 34 carries at itslower end a probing roller 37, running on a rotating cam 38. These cams38, arranged at each machine side, are fixed on a common cam shaft 39driven by a chain drive 40 from control shaft 17. The cams 38simultaneously act to hold the welding device 5 against action of thesprings 36 in its rest or inactive position. Cams 38 release springs 36during their rotational movement, and then the springs displace thewelding device 5 downwardly, whereby at first the clamping strips 29will press the foil 10 firmly against the clamping girders 28 and then,upon continued downward movement of arm 30, the hot wire 32 contacts andpasses through the foil 10 and, in doing so, cuts it and welds it atalong the two edges that develop at opposite sides of the cut as aresult of the cut. Thus the adjacent bag sides are welded shut at thispoint. Upon further revolution of the cams 38 Welding device 5 is againlifted into its rest position shown in FIG. 1.

The take-up and ejection device 6 is arranged forwardly of the weldingdevice and contains lower conveying belts 41 driven by a peripherallygrooved driving roller 42 and passing over tension and guide rollers 43.In preferred embodiment shown, several, for example four, conveyingbelts 41 are provided at a mutual lateral distance apart and runningparallel to each other. Above conveying belts 41, pressing belts 44 areprovided and these are similarly driven by a peripherally grooveddriving roller 45 and pass over tension and guide rollers 46. Thepressing belts 44 are provided in the same number and arrangement asbelts 41, one pressing belt 44 being above each conveying belt 41 in theassembly. For the drive of take-up and ejection device 6, a specialdriving motor 47 is provided controlled by switches 50* (FIG. 3)arranged on the control shaft 17. For uniform drive of conveying belts41 and pressing belts 44, the driving shafts of driving rollers 42 and45 carry intermeshing spur gears 48a and 48b at one of their ends. A camdrive is provided between driving motor 47 on the shaft of drivingroller 42 by chain drive 49. The driving motor 47 is such that thelinear running speed of both the conveying belts 41 and the pressingbelts 44 is higher in each case than the peripheral speed of the rubberfeed rollers 11 and 12 of the feeding device 4.

The method of operation of the machine shown in FIGS. 1 to 3 will now beexplained in detail with reference also to FIG. 4.

Upon switching on main supply switch HS, the heating circuit of theseparating and welding wire 32 is immediately energized through atransformer Tr or a series resistance. Also, upon closing of main switchHS, a voltage control instrument SG is activated immediately, whichsupplies the various control circuits of the machine. The main controlcircuit of the machine extends from control voltage device SG to asafety and time switch T, which is controlled by the heating circuit ofthe separating and welding wire 32. When the heating current is cut off,this safety switch opens and thus interrupts the main control circuit.Upon supplying the heating current to the separating and welding wire,first a time element contained in the safety and time switch T will act,which allows the main control circuit to be closed only after a certainamount of time has elapsed after switching on the heating current, whichis sufficient to heat the separating and welding wire to the requiredtemperature before the main control circuit is energized.

In the embodiment shown, the main control circuit runs from safety andthime switch T via two apparatus switches G51 and GS2 connected inparallel and one of which is to be operated by hand and the other onemay be operated automatically by a bag finishing device (not shown). Foroperation of the machine, closure of one of these switches GS13 or GS2is necessary, but both switches may also be closed at the same time. Themain control circuit runs from the switches G51 and GS2 to the switch-onwinding of a switch relay S1 for motor 15 of the drive for the foilfeeding device 4 and welding device 5. The energized motor 15 causes arevolution of the control shaft 17 on which cams 51 for the controlswitches 50 have been arranged. Furthermore, the revolving movement ofshaft 17 drives the feed device 4, so that the rubber rollers 11 and 12will take up a length of foil from roll 3 corresponding to the radialadjustment of the crank drive 18, 19, via the tensioning device 7 andthe guide rolls 8a and 8b, 8c. At the same time, when the foil 10 if asemi-tubular type foil, especially one with sides of varying length, theguide rollers 8a, 8b and 8c are made of metal and are in electricallyconductive connection with the machine frame, which itself will begrounded via the Zero conductor of the main supply grid connection.Therefore, the guide rollers 8a, 8b and 80 will bleed any accumulatedelectrostatic charge from the semi-tubular foil 10. The length of foildelivered by the rubber rollers is guided via the strippers 14 throughthe area of the welding device 5 and is grasped by the take-up andejection device 6. For control of the motor 47 of the take-up andejection device 6, a switch m3 is provided in the cam and switch set 50,51 on the control shaft 17, and applies control voltage from the controlvoltage device SG to the switch-on winding of the -switching relay S2 ofmotor 47. The take-up and ejection device 6, therefore, is switched onvia this secondary control circuit immediately after conclusion of themovement of the welding device 5 in order to eject the bag which hasjust been welded and separated, and to grasp and take up the next lengthof foil delivered and guided by the rubber rollers 11 and 12and topre-tension it for the next welding process. The time required for theoperation of welding device 5 is provided when the crank and the freerunning drive 18, 19, 20, 21 initially move through a no-load strokecycle as lever 21 moves freely on shaft 22 in a direction opposite tothat of the arrow. The effective driving stroke will move rubber rollers11 and 12 to deliver a length of foil to welding device 5 during thesecond half of the revolution of the control shaft 17 when lever 21moves in the direction of the arrow.

At the conclusion of the revolution of the control shaft 17, theswitches m1 and m2 contained in the set of cams and switches '50, 51 areoperated. The switch m1 switches the control voltage from the controlvoltage instrument SG to the shut-off winding of the relay S1, so thatmotor is switched off. The switch m2 switches the control voltage fromthe control voltage instrument SG to the charge winding of the relay S2,so that motor 47 is also switched off. The relays S1 and S2 can beprovided in a known manner with mechanical or electrical automaticholding arrangements which will keep the motor switches closed in thetime between actuating the switching-on winding and actuating theswitching-off winding.

A predetermined tension is maintained on foil 10 between the roll 3 andthe pair of rollers 11 and 12 up when they are not feeding foil by thelock pinion 27 on the upper rubber roller 11 and the brake provided inthe customary manner at the roll of foil 3. Through use of aself-locking geared motor 47 in the drive of the takeup and ejectiondevice 6, the tension on the length of foil extending from the feedrollers 11, 12 through the area of welding device 5 and taken up by thetake-up and ejection effective only when the welding process has beencompleted and the welding device 5 is again in its rest position and thetake-up and ejection device 6 has already started the ejection processof the finished bag. Because tension is constantly applied on the foil10, any clearance or play in the drive of the rubber rollers 11 and 12is taken up before the feed device becomes effective.

In the example of FIGS. 5 to 7, the basic structure of the bag sealingmachine is the same as that in the example of FIGS. 1 to 4, thereforethe same reference numbers are used for the same elements.

The bag sealing machine according to FIGS. 5 to 7 differs from the firstembodiment given by way of example of FIGS. 1-4 in that it includes asecond small sprocket wheel 11 attached on one end of the control shaft17, from which a driving chain 112 leading from wheel 111 to a sprocketwheel 113, which in disposed via an electrically controlled coupling 114on intermediate shaft 22. The electric coupling 114 is of a known typeand operates in such a way that it establishes a driving connectionbetween the sprocket wheel 113 and shaft 22, as long as electric currentflows through it. Whenever the flow of electric current is interrupted,the electrically controlled coupling 114 will interrupt the drivingconnection between sprocket wheel 113 and shaft 22. The remaining partsof the driving arrangement, that is to say the driving motor 15, thechain drive 16 to the chain wheel 18 on the control shaft 17, and thechain drive 23 on the shaft 24 of the lower rubber roller 12, are thesame as in the embodiment of FIGS. 1 to 4.

Photoelectric control assemblies 115 and 116 are provided for thecontrol of the electrically controlled coupling 114. These assemblies115 and 116 will be used alternatively and one of them must always beattached in the machine and must be in operation in order 0 operate theelectrically controlled coupling 114. As illustrated in FIG. 6, one ofthe photoelectric probing and control devices 115 is arranged along thepath of movement of foil 10 before the pair of feed rollers 11 and 12.This probing and control device 115 includes a lower part 117 containinga source of light, and of an upper part 118 containing the photoelectricelement, e.g. a photoelectric cell, a photoelement or a photoresistance.The two parts 117 and 118 are attached to a common support 119, which issupported from and guided along the inside of one of the lateralcarrying and mounting plates 2 in a slot 120. The probing and controlarrangement 115 can be adjusted by support element 119 along the path ofmovement of foil 10 to provide a desired width of the foil, so that thecut produced by the separating and welding wire 32 is properlypositioned to produce a bag of proper width. The probing and controldevice 115 operates in such a manner that the source of lightilluminates from the lower part 117 through the foil 10 andcorresponding to arrow 121, into the upper part 118. As long as thephotoelectric element 118 is illuminated, it maintains the circuit forthe coupling 114 in a closed state, so that transmission of drivingpower from the motor 15 up to feed rollers 11 and 12 occurs. As soon asa special marking imprint provided on foil 10, e.g. a control marking,comes into the area between the light source in the lower part 117 andthe photoelectric element in the upper part 118 of the probing andcontrolling device 115, the illumination of the photoelectric element isinterrupted and, as a result, the coupling 114 is deenergized so thatthe drive between the motor 15 and the feed rollers 11 and 12 isinterrupted, and the feed rollers 11 and 12 stop and cannot rotatebackwards because of the stop mechanism 27 that is built in. Foil 10provided with the proper marking imprints will thus be brought into theprecise welding position in order to seal a bag of predetermined width.

When the foil 10 is not provided with such marking imprints the secondprobing and control device 116 is utilized instead of assembly 115 andis attached to the machine in the area of the bag take-up and ejectiondevice 6. The probing and control device 116 consists of a light source122 directing a focused ray of light 123 on the sector 110 of the foilpassed or threaded into the bag take-up and ejection device 6, and of apart 124 containing the photoelectric element which receives the rays oflight 125 reflected by sector 110 of the foil. This probing and controldevice 116 operates in such a manner that it will keep the circuit forthe operation of the coupling 114 in a closed energized state as long asno light is reflected to the part 124, i.e., the sector 110 of the foilhas not come into the region of the light rays 123, so that the lightrays 123 will move forwardly along the direction of broken arrow 123. Assoon as the leading edge of sector 110 of the foil gets within the areaof light rays 123 and reflects the rays along arrow 125 into the part124 of the probing and control device 116, the circuit for the operationof the coupling 114 will be interrupted and the coupling will bedeenergized. As a result, the driving connection between motor 15 andfeed rollers 11 and 12 of the foil is interrupted, and the rollers willthen stop and be locked against backward reverse movement by the stopmechanism. Thus, the length of foil 110 will be measured precisely tocorrespond to the desired width of the bag, and will be positionedbetween the separating-welding device and the bag take-up and ejectiondevice 6. For a precise adjustment of the desired width of the bag, thetwo parts 122 and 124 are attached on a carrier plate 126, which can beadjusted along the path of movement of the foil in a slot 127 on theinside surface of one of the lateral carrier and mounting plates 2.

The method of operation of the bag sealing machine in this embodiment issubstantially the same in its essential parts to the method of operationof the embodiment according to FIGS. 1 to 4, with like reference symbolsapplied to like element in FIG. 7.

A bag forming process is initiated upon closure of one of the switchesG81 and GS2' which closes switch S1 to energize motor 15 and drivecontrol shaft 17 and cam shaft 39. The separating-welding process andthe control of the bag take-up and ejection device 6, therefore, runtheir course in the same manner as described in connection with FIG. 4.However, the control shaft 17 in its cam and switch set 50", 51 has anadditional control cam m4 and its cooperating controlled contacts. Thiscam m4- has been set up in such a manner that it will close its contactsas soon as the separating-welding device 5 has again been lifted orraised to its rest position through its cams 38. When this occurs, theexciter coil of switch S3 is fed current via the contacts of cam m4. Acoupling 114, designated with C in FIG. 7, is then excited via therectifier G and is coupled so that the driving connection from the motor15 to the feed rollers 11 and 12 is established. The feed rollers 11 and12 will then deliver a length to foil 110' past the separatingweldingdevice 5 into the bag take-up and ejection device 6.

As FIG. 7 shows, an operator may selectively introduce one of theprobing and controlling devices 115 and 116 into operation by means ofplugs 130, 131 and 132. If, for example, the probing and control device115 is to be used, the foil 10 provided with marking imprints 133 ismoved and delivered through feed rollers 11 and 12 until an imprint 133is positioned in the path of the light passing from the light source 134to the photoelectric device 13-5. The imprint 133 blocks passage of thelight between elements 134 and 135, which generates a control impulsewhich is carried to the release winding of the switch S3 to open switch8-3. As a result, coupling 114 is uncoupled and the driving connectionbetween motor 15 and feed rollers 11 and 12 is interrupted.

Since the feed rollers 11 and 1'2 must constantly operate against thepull created by the tension device 7 on the foil 10, the rollers uponinterruption of the driving connection by clutch 114 will immediatelystop, so that the length of foil which has been delivered correspondsprecisely to the distance between successive imprints 133.

When the probing and control device 116 is to be used the light rays123, produced by the light source 122, will initially pass in thedirection of arrow 123. As s o as the leading edge of foil sector 1-10reaches the region of light rays 123, the light is reflected in thedirection of arrow 125 to the photoelectric device 124 to produce animpulse which is fed to the release coil of switch S3. This causesswitch S3 to open and the coupling 114 to be released therebyimmediately stopping the feed rollers 11 and 12.

In both cases the transmission ratio of chain drives 112, 113, 23, 24 issuch that the drive of the feed rollers 11 and 12 corresponds to only arelatively small fraction, e.g. one-fourth of a revolution of thecontrol shaft 17. The coupling 11'4 therefore, is released before thecontrol shaft 17 has executed or completed one full revolution. Motor 15then continues to run in order to drive the control shaft 17 through acomplete revolution of 360". During the last part of this revolvingmovement of the control shaft 17, the switch 1112 for stopping the bagtake-up and ejection device 6 and the switch ml for stopping motor 15are operated in the same manner as described above with reference toFIG. 4. The two light sources 134 and 122, according to the arrangementof FIG. 7, are switched on continuously during the operation of themachine via the transformer Tr2. However, it is also possible to connectthe light sources 134 and 122 from the transformer TrZ via the plugs130, 131 and 132, so that only the light source 134 or 122 of theselected probing and control device or 116 which is in operation willreceive current.

:FIGS. 8 to 15 show additional embodiments of bag sealing machines wherea semi-tubular foil 10 made of thermoplastic synthetic material or athermoplastic foil previously folded in longitudinal direction is fedintermittently in lengths corresponding to the desired width of the bagto a separating-welding arrangement. The separating-welding arrangementin the case of the bag seal ing machines in FIGS. 8 to 15, for asimultaneous separation and welding of the foil 10, operates at theproper separating edges with a heated separating-welding element 32,which for this purpose is guided essentially perpendicularly from aboveto below through the foil 10 and subsequently between the welded edgesfrom below to above back into the rest position.

The device shown in FIGS. 8 to 15 form an especially complement for thebag sealing machines described above but they can also be used with bagsealing machines whose foil feeding arrangements differ from thosedescribed above.

'In the embodiment illustrated in FIGS. 8 to 11, additional structure isprovided at both sides of the separating and welding wire to lift thewelded bag edges from the area of movement of the wire 32. For thispurpose on one s1de of wire 32 a flap 61 is attached inside the lowerclamping girder 28, and is mounted on a horizontal rotatable shaftextending parallel to the lower clamping girder .2 8, the shaft havinglever 62 extending obliquely downwardly therefrom. The plunger 63 of anelectromagnetic coil 64 is connected to lever 62, so that uponenerglzation of coil to pull plunger 63, the flap 61 will swing upwardlyinto the position shown in a broken line in FIG. 8 and full line of FIG.11. For the purpose of receiving the flap, both clamping girders 28 and2-9 have an L-shaped profile 'as shown in FIGS. 8 to 11.

A pair of brackets 65, 66 are arranged on the other side of theseparating and welding wire 32 between the wire and the take-up andejection device 6 as a second device to lift the welded edge from thearea of movement of the separating and welding element 32. The upperbracket 65 is held similarly to the upper clamping girder 29perpendicularly slidably on the guide and bearing arm 30 against theaction of a spring 67. The lower bracket 66 is guided axially slidablyby at least one, preferably two, rods 70 at point 71 between holding andmounting plates 2 and at points 72 and 73 inside the machine frame 1. Aspring 75 which urges the bracket rod 70 downwardly is positionedbetween the upper guide 71 and a collar 74 attached to the rod 70. Eachbracket rod 70 carries at its lower end a follower roller 76, which runson a cam 77. The cams 77 are attached on the same shaft 39 as are theoperating cams 38 for the separating-welding device 5, so that the lowerbracket 66 is controlled positively together with the separating-weldingdevice 5.

The operation of the embodiment shown in FIGS. 8 to 11 will now bedescribed.

If, as shown in FIG. 8 a length of foil corresponding to thepredetermined desired width of the bag is positioned between feedrollers 11 and 12 and conveying belts '41 and the pressing belts 44, thecam shaft 39 controlling sealing device is rotated by operation of thecontrol system described above. As shaft 39 and cams 38 and 77 rotatecounterclockwise from the position of FIG. 9 roller 37 will ride ontothe flat area of cam 38 thereby causing spring 36 to pull the guide andcarrying arms 30 together with the separating and welding wire 32, theupper clamping girder 29 and the upper bracket 65 downwardly. In theposition shown in FIG. the upper clamping girder 29 rests on the foil 10and the upper bracket 65 with its bracket carrier 68 rests against astop 69 attached to the guide and mounting plates 2. In this position ofthe device, the foil 10 is clamped firmly between girders 28 and 29 onone side of wire 32 in the direction of the feed rollers 11 and 12. Theupper bracket 65 has progressed with its lower edge to below the planeof the foil 10 and has, as a result of that somewhat pulled back thelength of foil 110 between the conveying belts 41 and the pressing belts44 and clamped and tensioned them across the upper edge of the lowerbracket 66. As a result, the brackets 65,66 function as a pair ofsmoothing strips, which produce a fold-free stretching of the foil 10 inthe operational region of the separating-welding device 5. Uponcontinued downward movement of the guide and carrying arms 30, the upperclamping girder 29 and the upper bracket 65 will stop, so that thesprings 31 and 67 will be compressed. The separating and welding wire 32will pass through the foil and sever the latter, whereby each of the twosevered edges of the foil i welded as to form the lateral seams or sideedges of adjacent bags. As cam shaft 39 continues to rotate, roller 37again runs onto a raised part of the cam 38 to initiate upward movementof the guide and carrying arms 30. Simultaneously, the following rollers76 run up on the raised part of cam 77, so that the lower bracket 66 islifted vertically to a position horizontally aligned with the upperbracket 65. With that, the second lateral edge of the length 110 of thebag, which has just been produced, is lifted, as FIG. 11 shows, from thepath of movement of the separating and welding wire 32. At the sametime, the relay 64 is activated from the main control, so that it willpull its plunger 63 and thus deflect the flap 61 upwardly in the freespace formed by the L-profile of the two clamping girders 28 and 29 and,as a result, will lift the first welded edge of the next foil lengthupwardly out of the area of movement of the separating and welding wire32. The separating and welding device 5 can thus move back upwardly intoits rest position, without the separating and welding wire 32 cominginto contact with the previously formed welded edges. The cam shaft 39will revolve back to its normal position, shown in FIG. 9 in which theroller 37 rests on the highest projection of cam 38 and the probingroller 76 on the flat part of cam 77, thereby returning the lowerbracket 66 to its normal position, shown in FIG. 8 under the action ofthe spring 75. In addition the main circuit control will run up to itsnormal position, in which the relay 64 is deenergized and the operatingbar 63 has returned again into its extended position, shown in FIG. 8under the action of built-in spring, and the flap 61 will again bepivoted back into the flat rest position. The described operation willthen be repeated to form a desired quantity of bags.

In the embodiment illustrated in FIGS. 12 and 13, the basic structure ofthe device is substantially the same as that shown in the example ofFIG. 11 with like parts being designated by like numerals.

In the embodiment of FIGS. 12 and 13, only the upper bracket 65 and thelower bracket 66 have been provided to lift the welded edge of theformed bag'from the area of movement of the separating welding wire 32and to function as a pair of smoothing elements. The construction ofthese brackets 65 and 66, as well as their method of operation, are thesame as those in the embodiment of FIGS. 8 to 11.

In the embodiment of FIGS. 14 and 15, the same structure of the bagsealing machine and its separating-welding device 5 are assumed to existas in the example of FIGS. 8 to 13 so that like parts again areindicated by like reference numerals. However, in the example of FIGS.14 and 15, the foil smoothing function and the finished bag edge liftingfunction are performed by separate apparatus. To accomplish this theguide and carrying arms 30 at the side facing the take-up and ejectiondevice 6 carry an upper smoothing strip 81, which is attached to theguide and carrier arms 30 and is slidable therealong against the actionof springs 82. This upper smoothing strip 81 acts together with thelower smoothing strip 83 attached firmly to the machine frame. Inaddition, the lower fixed smoothing strip is provided on its topsidewith a bevel 84 directed backwardly and downwardly, while the uppersmoothing strip 81 has a lower edge 85 formed by two bevels, whichsettles at a distance behind the bevel 84. Upon downward movement of theguide and carrier arms 30, the upper smoothing strip will reach itslowest position when its projection 86 abuts stop 87 fixed to the frame.In this position the lower edge 85 of the upper smoothing strip 81 liesat a horizontal distance behind bevel 84. At the same time, the uppersmoothing strip 81 through its lower edge 85 will pull the foil length110 back somewhat between the conveying belts 41 and the pressing belts44. As a result, the foil 10 will be held without jamming, as can beseen in FIG. 14, between the smoothing strips 81 and 83 and is stretchedsmooth in the area of the separating-welding device 5.

In the example of FIGS. 14 and 15, two flaps 91 and 92 are provided tolift the just welded edges from the path of movement of the separatingand welding wire 32. The flap 91, lying in the direction toward the feedrollers 11 and 12 are pivotally mounted in the lower clamping girder 28,as in the example of FIGS. 8 to 11. It is held in its normal positionshown in FIG. 14 by means of a spring not shown here. For the purpose ofswinging flap 91 upwards, at least one of the guide and carrying arms 30carries a driver hook 93, which is pivotally mounted around an axis 95at the upper part of the hook shaft counter to the action of a spring94. The flap 92, arranged between the separating and welding wire 32 andthe takeup and ejection device 6, as shown in FIGS. 14 and 15, has aswiveling lever 96, which is connected to the shaft 97 of anelectromagnetic relay 98. The shaft 97 is held in its rest position,shown in FIG. 14, by means of a spring 99, whenever the relay 98 isdeenergized and upon excitation of the relay 98, it is pulled into theposition shown in FIG. 15, in which the flap 92 is pivoted upwardly bylever 96 as shown in FIG. 15.

Starting from the position of FIG. 14, if the guide and carrier arms 30are moved downwardly in the direction of the arrow during the separatingand welding process, the heated separating and welding wire 32 passesthrough the foil to sever it and simultaneously to form and weld twoedges of successive bags. During this downward movement, the driver hook93 passes around the free edge of flap 91 and at the same time, thedriver hook 93 will stop under the effect of the spring 94 behind thefree edge of the flap. The downward movement in the direction of arrow100 and the subsequent movement upward in the direction of arrow 101 isproduced in the same manner as explained in connection with the exampleaccording to FIGS. 8 to 11. Upon beginning the upward movement in thedirection of arrow 101, the relay 98 is energized by the main circuitcontrol, so that it will pull shaft 97 against the action of spring 99and will pivot flap 92 upwardly. As a result, as shown in FIG. 15, thesevered end of the bag length 110 provided with the welded edge ispulled back between the smoothing strips 81 and 83 and out of the areaof movement of the separating and welding wire 32. In the case of theupward movement of the guide and carrier arms 30, the driving hook 93also carries the free edge of flap 91 upwardly, so that this flap 91 issimilarly swung upwardly, and, in doing so, will lift the just formed,welded edge of foil 10 from the area of movement of the separating andwelding wire 32. Toward the end of the upward movement in the directionof arrow 101, the fiow of current through relay 98 is switched off, sothat its plunger 97 returns to its rest position as in FIG. 14, underthe action of spring 99 and pivots flap 92 back to its startingposition. During the upward movement in the direction of arrow 101, thedriver hook 93 runs oi the free edge of the flap 91, so that flap 91 toowill return to its rest position, shown in FIG. 14, through its returnspring or at least because of its own weight. The return of flaps 91 and92 into their rest position, however, takes place at a time when theseparating and welding wire 32 has already been lifted to a point whereit can no longer come into contact with the previously formed weldededges.

What is claimed is:

1. A machine for forming bags from a continuous Web of semi-tubular foilof thermoplastic synthetic material or a previously longitudinallyfolded foil of such material comprising intermittent feed means forperiodically advancing said Web in a predetermined direction andcomprising a pair of rotatable feed rollers defining a pass betweenwhich said foil is received and drive mechanism for intermittentlyrotating said rollers, stop mechanism permitting rotation of saidrollers only in the foil feeding direction, foil severing and weldingmeans in the path of said web operated in synchronism with saidintermittent feed means for severing the web into succes sive sectionsof predetermined length corresponding to the desired bag width andWelding together the severed edges of the web and the severed sectionlying at opposite sides of said severing and welding means, bag feed andejection means for moving the formed bags in succession away from saidsevering and welding means, drive means for said bag feed and ejectionmeans, and means for controlling actuation of said bag feed and ejectionmeans in timed relation with said intermittent feed means and saidsevering and welding means.

2. Bag forming machine according to claim 1, wherein said rollers aremutually driven through cooperating spur gears, and said stop mechanismacts between a shaft casing one of said rollers and the frame of saidmachine.

3. Bag forming machine according to claim 1, wherein the drive mechanismfor said foil feeding rollers includes a crank assembly with an attachedfree-wheeling rocking lever drive, said crank assembly being adjustableto vary the foil lengths fed toward said severing and welding means.

4. Bag forming machine according to claim 1, wherein said drivemechanism for said foil feeding rollers includes an electricallycontrolled coupling element for interrupting the drive connection tosaid feed rollers, and probing means arranged along the path of movementof the foil for controlling said coupling element.

5. Bag forming means according to claim 4, wherein said probing means isadjustable along the path of movement of the foil for selecting adesired width of the finished bag.

6. Bag forming machine according to claim 4, wherein said probing meanscomprises a photoelectric probing device which responds to markingimprints aflixed on said 12 foil at regular intervals corresponding tothe desired width of a bag, said photoelectric device being operative todeenergize said coupling element in response to sensing one of saidimprints, thereby interrupting the driving connection for said foilfeeding rollers.

7. Bag forming machine according to claim 4, wherein said probing meanscomprises a photoelectric probing device which responds to thepositioning of the leading edge of said foil in said bag feed andejection device, said photoelectric device being operative to deenergizesaid coupling element to interrupt the driving connection to said foilfeeding rollers.

8. Machine for forming bags made from a semi-tubular foil ofthermoplastic synthetic material or a foil folded previously inlongitudinal direction, comprising a feed de vice for feeding apredetermined length of foil corresponding to the desired width of thebag intermittently to a welding device which simultaneously severs thefoil and welds the foil along the adjacent severed edges with a heatedsevering-welding element, means for moving and guiding said severing andwelding element for movement from a rest position through said foilduring which time it severs and welds said severed edges of said foiland for subsequently moving said element back to said rest position, andmeans positioned adjacent at least one side of said welding element forlifting the welded edge lying on that side from the area of returnmovement of said severing-welding element.

9. Machine according to claim 8, wherein said welded edge lifting meansis on the side adjacent said bag take-up and ejection device.

10. Machine according to claim 8, wherein said welded edge lifting meansis provided on both sides of said severing-welding element.

11. Machine according to claim 8, wherein said lifting means comprises anarrow flap positioned below said foil and transversely across its widthand controlled to pivot upwardly upon upward movement of saidsevering-welding element.

12. Machine according to claim 11, wherein said flap is operated by adriver hook attached to said welding device, said hook pivots said flapupwardly upon upward movement of said severing-welding element and upondownward movement of said severing-welding element resiliently engagesunder the free edge of said flap,

13. Machine according to claim 11, wherein said flap 1s operated by arocking lever connected to an electromagnetic relay controlled from amain circuit control.

14. Machine according to claim 8, wherein said lifting means comprises apair of brackets acting against each other from above and below andagainst the welded edge area of said foil and lifting the welded edgefrom the area of movement of the severing-welding element, one of saidbrackets being resiliently and slidably arranged and guided for movementrelative to said foil on guide and carrier arms for the severing-Weldingelement, the other of said brackets being movable relative to said foiland operated by a suitably driven cam mechanism.

15. Machine according to claim 14, wherein said upper bracket is spaceda longitudinal distance from the severing-welding element on one side ofsaid foil and said lower bracket is positioned to be moved within saidspace from the other side of said foil.

16. Machine according to claim 8, wherein a pair of girders clamp thefoil at the feed side of said severingwelding element and a pair ofsmoothing strips tension the foil without clamping it on the exit sideof said separating element.

17. Machine according to claim 16, wherein said smoothing stripscomprise a pair of brackets which lift a welded edge from the area ofmovement of said severingwelding element.

18. A machine for forming bags according to claim 1, wherein said meansfor controlling actuation of said bag feed and ejection means isoperated by said roller drive mechanism.

19. A machine for forming bags according to claim 1, wherein said feedrollers drive mechanism is adjustable to determine the length of eachsaid section and thereby the width of the formed bag.

20. A machine for forming bags according to claim 1, wherein said rollerdrive mechanism comprises power means connected to intermittently rotateone of said rollers, said one roller is connected to positively drivethe other roller, and said stop mechanism is operatively effective uponsaid other roller.

21. A machine for forming bags according to claim 1, wherein a firstmotor is connected to drive both said feed rollers and said severing andwelding means, and a second motor is connected to drive said bag feedand ejection means, and a control circuit is provided to synchronizeactuation of said second motor with said first motor.

22. A machine for forming bags according to claim 1, wherein said feedroller drive mechanism comprises an electric motor drive connected to arotatable control shaft, means is provided connecting said control shaftto intermittently rotate said rollers, an electric motor is driveconnected to said bag feed and ejection means, and means is provided onsaid control shaft for timed actuation of switches in a main circuitcontaining both of said motors.

23. A machine for forming bags according to claim 22 wherein saidsevering and welding means comprising an electrically heated element andsaid main circuit contains timing means that delays operation of saidmotors until said element has reached foil fusing temperature.

24. A machine for forming bags according to claim 23, whereincam meansis provided for periodically operating said severing and welding meansand a drive connection is provided between said control shaft and saidcam means.

25. A machine for forming bags according to claim 24, wherein meansactuated by said cam means is provided for displacing at least one ofsaid welded foil edges out of the path of the severing and welding meansupon conclusion of a severing and welding operation.

26. Bag forming machine according to claim 1, wherein means is providedfor maintaining the foil under tension between the feed rollers and saidbag feed and ejection means whereby to accurately determine the locationof the severing and welding operation.

27. Bag forming machine according to claim 1, wherein said bag feed andejection means comprises a plurality of 14 laterally spaced lowerconveying belts and a corresponding plurality of aligned upper pressingbelts, said belts having common driving means.

28. Bag forming machine according to claim 27, wherein the conveyor andpressing belts are controlled for intermittent operation so that theywill move only during a bag ejection process following welding.

29. Bag sealing machine according to claim 27, Wherein at least theoutside conveyor belt running at the open side of the bag and thepressing belt aligned with it are set back against the opening edge ofthe bag.

30. Bag forming machine according to claim 27 wherein said belts arenon-metallic plastic, and said feed rollers are rubber covered.

31. Bag forming machine according to claim 1, wherein said roller drivemechanism and said foil severing and welding means are driven from acommon first motor, and said bag feed and ejection means is driven froma second motor.

32. Bag forming machine as defined in claim 1 wherein said bag feed andejection means moves said formed bags at a higher linear speed than saidweb is advanced by said feed rollers.

33. Bag forming machine according to claim 1, wherei in said severingand welding means comprises a vertically reciprocable electricallyheated element, cam means is provided to lift said element against theaction of biasing spring means to a rest position above the path ofmovement of the foil and then release the element to descend for thesevering and welding process under the action of said spring means.

References Cited UNITED STATES PATENTS 2,683,401 7/1954 Smith 156-5832,749,817 6/1956 Piazze et al. 156-583 2,947,345 8/1960 Schjeldahl156-361 3,053,723 9/1962 Plach et al. 156-511 3,185,609 5/1965 Merithewet al. 156-583 3,192,095 6/1965 Doyen et al. 156-583 3,330,716 7/1967Zelnick 156-499 3,481,376 12/1969 Keller 156-583 ROBERT F. STAHL,Primary Examiner US Cl. X.R.

UNITED STATES PATENT OFFICE CERTIFICATE OPT/CORRECTION Patent No. 3,586, 577 Dated June 22, 1971 Inventor(s) ITALO DELLA BELLA It iscertified that error appears in the above-identified patent and thatsaid Letters Patent are hereby corrected as shown below:

Column 5, line 2, change "thime" to --time-.

Column 5, line 7, change "13" to -l--.

Column 5, line 74, before "effective" insert --device 6 is maintained.The drive of the feed device 4 becomes-.

Column 6, line 15, change "in" to -is--.

Column 6, line 33, change "0" to --to-- Claim 2, column 11, lines 55 and56, "casing" should be -carrying.

Claim 24, column 13, line 32, change "23" to --22.

Signed and sealed this 28th day of December 1971 (SEAL) Attest:

EDWARD M.FLETCHER,JR. ROBERT GOTTSCHALK Attesting Officer ActingCommissioner of Patents FORM P0-1o50 (10-69) USCOMM-DC G037G-F'69 9 U SGOVERNMENY PRINTING OFFICE: I969 0-365-334

